1. Field of the Invention
The present invention relates to a process cartridge which is mounted on an image forming apparatus, such as a laser printer or a copying machine, a photosensitive drum unit which is disposed in the process cartridge, a developing roller unit, and an end member.
2. Description of the Related Art
In an image forming apparatus which is represented by a laser printer or a copying machine, a process cartridge which is attachable to and detachable from a body (hereinafter, referred to as an “apparatus body”) of the image forming apparatus is provided.
The process cartridge is a member which forms contents to be expressed by letters or figures and transfers the contents to a recording medium, such as a paper sheet. Therefore, in the process cartridge, the photosensitive drum in which the transferred contents are formed is included, and various devices for forming the contents to be transferred by acting on the photosensitive drum are disposed together. Examples of these devices include a developing roller unit, a charging roller unit, and a device for performing cleaning.
The process cartridge is so configured that the same process cartridge is attached to and detached from the apparatus body for maintenance, or a new process cartridge is mounted on the apparatus body instead after disengaging an old process cartridge from the apparatus body. Attaching and detaching the process cartridge in this manner is performed by users of the image forming apparatus themselves, and it is desirable to perform attaching and detaching as easily as possible.
Meanwhile, it is necessary that the photosensitive drum included in the process cartridge is rotated around a shaft line during the operation thereof. Therefore, the photosensitive drum is configured to be engaged with a driving shaft of the apparatus body directly or via another member at least during the operation, to receive a rotating force from the driving shaft, and to rotate. Therefore, in order to attach and detach the process cartridge to and from the apparatus body, it is necessary to release (disengage) the engagement between the driving shaft of the apparatus body and the photosensitive drum every time attaching and detaching occur, and to mount the process cartridge again.
Here, if it is possible to move the photosensitive drum (process cartridge) in the shaft line direction of the driving shaft of the apparatus body, and to attach and detach the photosensitive drum, the above-described structure for attaching and detaching is relatively simple. However, from the viewpoint of reducing the image forming apparatus in size or ensuring an attachment and detachment space of the process cartridge, it is preferable to disengage the process cartridge from the apparatus body to be pulled out in the direction which is different from the shaft line direction of the driving shaft, and to mount the process cartridge on the apparatus body to be pushed in this direction.
In Patent Literature 1, a technology in which the driving force from the apparatus body side is transferred to the photosensitive drum when a cover of the apparatus body is closed, and movement to be separated is performed so that the driving force is not transferred to the photosensitive drum when the cover is opened, is disclosed. Accordingly, the process cartridge can be attached to and detached from the apparatus body in the direction which is different from the shaft line direction of the driving shaft.
In addition, in Patent Literature 2, an invention in which the driving shaft of the apparatus body and the photosensitive drum are engaged with each other via a rotating force transmission component having a trunnion structure attached to the photosensitive drum, and the photosensitive drum is rotated, is disclosed. Since the rotating force transmission component can change an angle with respect to the shaft line of the photosensitive drum by the trunnion structure, engagement and disengagement between the driving shaft of the apparatus body and the photosensitive drum unit is easy.
In Non-Patent Literature 1, a technology in which a bearing member of the photosensitive drum unit engaged with the driving shaft is provided to be movable in the shaft line direction by an elastic member, such as a spring, is disclosed. Accordingly, while the bearing member is biased by the elastic member when attaching and detaching the bearing member and the driving shaft, the attachment and the detachment are smoothly performed by moving and retreating in the shaft line direction.    Patent Literature 1: Japanese Patent No. 2875203    Patent Literature 2: JP-A-2008-233868    Non-Patent Literature 1: Japan Institute of Invention and Innovation, Journal of technical disclosure 2010-502197